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307

5
th

International DAAAM Baltic Conference


INDUSTRIAL ENGINEERING


ADDING INNOVATION CA
PACITY OF LABOUR
FORCE AND ENTREPRENE
URS



20

22 April 2006, Tallinn, Estonia


INTENSIFICATION OF TECHNOLOGICAL PROCESSES

WITH ELECTROMAGNETIC IMPULSES


Zemchenkovs
, V.
,

Mironov, V.
,

Viba, J.



Abstract:
Forming of guided
electromagnetic impulses by the generators
with or not of condensers allows design they
efficiency in the field of intensification
various technological processes in
metallurgical engineering, for

transport dry
materials, metal working and mechanical
engineering.

Control of amplitude and time of force
impulse may be realized by voltage and
condenser parameters as well as by
variation parameters of inductor and
concentrator of electromagnetic field.

Use of new technology is given: for
magnetic
-
impulse powders pressing,
acceleration of material flow out processes
from bunkers, disarrangement and
transport powders. Schemes of realizing any
processes and obtain properties are given.

Key words: electroma
gnetic field, dry
material, processes intensification.


1. INTRODUCTION


Methods of processes intensification for
production and transport dry materials have
very importance in the various industry
branches. The main area of they using is
discharge and dos
ing materials, compacting
of powders, obtain mixture and they sorting.
Exist various methods of technological
processes intensification, for example, use
of vibration, mechanical loosen, mechanical
shaking [
1
]. Similarly utilization of
ultrasound vibration
s, electrical discharge
and electromagnetic fields is known [
2
]. In
this report methods of technological
processes intensification for production and
transport dry materials by use of electro
impulse generators are observed. Interest to
these methods is de
termined by generation
of last year’s very high efficiency and
compact electro impulse generators [
3, 4
].


2. GENERATION OF ELECTRO
IMPULSE FORCE ACTION


Electro impulse force action is generated by
electro impulse generator condenser model.
Change voltage

of generator’s charge may
be controlled amplitude and time of current
inside inductor and respectively may be
obtained various step of force impulse
action of electro magnetic field interaction
(Fig. 1.).



Fig. 1. Parameters of impulse current charge
i
(t),
pressure
p
(t),

velocity
v
(t)
and
displacement
v(t)

at frequency of discharge
10

kHz (a) and 100

kHz (b)
.


The main equations of calculation are [6]:


t
e
I
i
t
m


sin
2


;

(1)




t
H
p
2
0
2


,

(2)

where
I
m



maximal value of discharge
cu
rrent;


308

α


coefficient of damping;

ω



angular frequency;

H



voltage of magnetic field inside
inductor;

p



pressure of electric magnetic
field;

μ
0



magnetic constant.

Efficiency of impulse action much depends
of electro conductivity of preparation
mat
erials in which acted electro magnetic
field, as well ass of it strength and plasticity
properties.


3.

INTENSIFICATION OF POWDERS
COMPACTING PROCESSES


Pressing powders materials inside matrix
often do not reach high density of materials
which depends of
plastic deformation of
powder [
2
]. To get density more about 80 %
or for pressing small dispersion powders
needs very high pressing force.

This force decrease may be realized by
additional impulse force loading. One of the
respectively method in this dire
ction is
combined compacting in which in time of
pressing by hydraulic or mechanical press
the additional impulse forces to powder
material is added from impulse electro
magnetic field [
7
]. The scheme of
equipment is shown in Fig. 2. In one cycle
of punch
strike 3
-
4 impulses are added.





Fig. 2. Scheme of combined pressing by use
of electromagnetic impulse generator

(
p
imp.max
= 250 MPa
,
p
CT
= 400

MPa).


The method allows arise density above 5
-
10

%, implement pressing small layers with
difficult materials

as well as obtain
multi
layer product (Fig.

3).




Fig. 3. Multilayer product made of
sand


cement mixture covered by Si,
obtained with impulse electromagnetic field
(200 x 150 x 20 mm) [
7
].


4. SINTERING OF POWDERS WITH
APPLIED FORCE IMPULSES


The metho
d of sintering, connected with
impulse packing is interesting for cover
surface with powders composite materials,
for example, blend of ferrous powders and
ftoroplast materials.

Powder mixture first regular distributes
along detail surface and then put int
o
ceramic form between two electrodes (Fig.
4).

In the processes of accumulate energy
discharge simultaneously take place
powders packing and sintering.

As parameter of main technology efficiency
is assume value of current density (
i
е
), flow
through powde
r:



n
S
I
i
m
e

;

(3)


where
I
m



maximal value of discharge
current;

S



area of covered surface;

n



number of discharge impulses;

τ



duration of discharge impulse.


309


Fig. 4. Scheme of impulse loading
combined sintering.

1


capacity accumu
lator; 2


matrix; 3


electro conductive plate; 4


inductor; 5,6


punches; 7


powder.


How investigation shows the high quality of
cover may be obtained in a case when initial
density of porous layer is more 60%. If
density is less this level the irreg
ular coating
take place by not uniform distribution of
impulse current inside volume of material.

Obtained data of material properties is given
in table

1.


Table 1. Exchange of relative density
Θ

and
strength of adherence
σ
s

for ferrous powder
ASC 100.29 under iron pallet with electro
sintering by additional impulse loading.


Parameters of process

Property
of
powders

i
е
,
kA

Pres
-
sure


p
max
,
MPa

Amount
of
impulses,
n

Θ
,
%

σ
s
,
N/м
м
2

150

120

1

86

72

300

120

2

92

90

450

120

3

95

125

150

180

1

91

90

300

180

2

96

116

450

180

3

97

134





5. INTENSIFICATION OF
TRANSPORT PROCESSES BY DRY
MATERIALS


In Riga Technical University made impulse
method for transport ferromagnetic powders
[3]. For this r
eason were created some series
compact impulse current generators with
capacity from 0
.
5 kJ to 2 kJ. On the base of
this generator experimental device allows
transporting ferromagnetic powder (powder
of ferrous AHC) straight vertically with
mass 1 kg in th
e one impulse cycle at the
height more 2 m.

Very important are devices of use magnetic


impulse driver with common vibration
and shock action mode. Experimental
device was made on the base of generator
Impulse


BM

6 (Fig. 5.). In this system
plane induc
tor is mounted on the plate of
device. Electromagnetic action has
frequency from 50 to 220 cycles/min.

Device allows realize ferromagnetic
powders transporting and they dosing. Plane
inductor may be mounted on the
wall of
bunker (Fig. 6
). Then impulse act
ion
increase dry material flow velocity through
bunkers outlet hole
(Fig. 7
).




Fig. 5.
Generator Impulse


BM 6:

(
ω
max

=
0
.
6 kJ;
U
max

=
6
-
11 kV;
n
max

=
220)




310


Fig. 6. Plane inductor mounted on the wall
of bunker


Fig. 7. Scheme of device
for dr
y materials
bunker shaken:
1


灯睤e爻′



睡汬映
扵湫b爻″r


楮摵捴潲㬠㐠


業灵汳攠pe湥牡瑯t


CONCLUSION


1. Use of electromagnetic impulses open
long
-
range possibilities for intensification of
different technological processes.

2. By the exchange param
eters of
electromagnetic impulse generator may be
controlled amplitude and time of impulse
action as well form of impulse and it
frequency.

3. Investigations of impulse generators
allow design new combined presses.


REFERENCES


1.

Vibration in
Technique. Han
dbook,
1978, vol.
1. Edited by Bolotin, V.V.
Machinostroenie. Moscow (in Russian).

2.

Electrochemical and electrophysical
methods of treatments. Handbook, 1988.
Edited by Volosatov V.A., Machino
-
stroenie. Leningrad (in Russian).

3.

Mironov V., Viba J. Device for

transportation of powders in a vertical
pipe by a pulse electromagnetic field.
In
Conf. “Industrial Engineering”, April
2002, Tallinn, Estonia, 193
-
196.

4.

The small
-
sized impulse electro
-
magnetic generator.

Hi
-
tech in Latvia,
2001, Riga.

5.

N. Dorozhkin, V. Mi
ronov, V. Vere
-
shagin, A. Kot.

Electrophysical coatings
from metallic powders. Riga
, Zinatne,
1985

(in Russian).

6.

Mironov V. Magnetic pulse pressing o
f
powders. Riga, Zinatne, 1980
(in

Russian).